H1N1 flu plus MRSA blamed for 2009 deaths in healthy children

Kathleen Blanchard's picture
H1N1 flu combined with MRSA claimed lives of previously healthy children in 2009
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MRSA made H1N1 flu deadly for children in 2009. Investigators have unraveled a mystery about why H1N1 flu made so many children critically ill in 2009 and why so many died. According to a finding that researchers say is “alarming”, many previously health children also developed methicillin resistant staph aureus (MRSA) infection leading to respiratory failure and death.

Scientists say MRSA becomes more invasive in the presence of flu and other viruses.

But the alarming part of the discovery is that children were treated quickly with Vancomycin – a drug that should wipe out MRSA, yet they still died.

MRSA is rampant in the community. A 2010 study showed most cases of MRSA are acquired outside of the hospital. The study, published in the journal Pediatrics, found an increase in the number of children hospitalized for methicillin resistant staph aureus from 1999 to 2008.

One of the reasons for rising MRSA cases is overuse of antibiotics in humans and animals.

The authors say MRSA pneumonia hasn’t been found to be a common cause of pneumonia in children.

When H1N1 flu and other viruses weaken the immune system, the bacteria, which are opportunistic, can enter the bloodstream; affecting the lungs, heart, bones and joints. The researchers say there may be something “synergistic” about MRSA, combined with H1N1 flu that makes the bacteria more virulent.

The researchers aren’t sure why Vancomycin didn’t work to save children with H1N1 flu in 2009. They speculate the disease either progressed rapidly or the drug couldn’t penetrate the lung tissue.

The study, conducted by researchers at Children’s Hospital Boston, found most children who were critically ill with H1N1 flu in 2009 were age 6.

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Adrienne Randolph, MD, MsC, of the Division of Critical Care Medicine at Children's Hospital Boston says "These deaths in co-infected children are a warning sign” that it’s important for kids to be vaccinated against H1N1 flu, which is expected to make its rounds again this year.

"The 2009 H1N1 virus has not changed significantly to date," said Tim Uyeki, MD, MPH, of the Influenza Division of the National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention (CDC), a senior investigator on the study.

Infections of children in the U.S. with 2009 H1N1 virus are expected this season and need to be prevented and treated appropriately. Influenza vaccination protects against 2009 H1N1 illness."

For the study, published in the journal Pediatrics, researchers tracked 838 children with probable H1N1 flu who were admitted to pediatric intensive care units throughout the country, from April 2009 to April 2010. H1N1 flu vaccine became available in September, 2009. Vaccine status of the children was unknown.

Among the children studied, 30 percent were previously healthy. Most of the children had respiratory failure; two-thirds required support through mechanical ventilation and some required advanced heart and lung support known as EMCO (extracorporeal membrane oxygenation).

Randolph explains hospitals were overwhelmed with the number of sick children from H1N1 flu.

"Early in the pandemic, centers were worried that they would run out of ventilators; that they would run out of ICU beds."

While many of the children had other health problems, those who were previously healthy were found to have only one risk factor for becoming critically ill. The presumption is they had MRSA, which increases the risk of dying 8 fold in the presence of H1N1 flu.

“Unfortunately, these children had necrotizing pneumonia – eating away at their tissue and killing off whole areas of the lung. They looked like immunocompromised patients in the way MRSA went through their body. It's not that flu alone can't kill – it can – but in most cases children with flu alone survived."

The study is the first to find such a large number of children with H1N1 flu and MRSA combined. The study authors say developing a vaccine for MRSA would be difficult. For now, the best way to protect children from H1N1 flu deaths is through vaccination. They also note the importance of finding ways to prevent colonization of MRSA in the community.

Image credit: Wikimedia commons

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